The prevalence of overweight and obesity among children and adolescents has increased all over the world and has reached alarming proportions, especially in industrialized countries.1,2 Obesity during childhood and adolescence is of major concern given that obese children and adolescents are at higher risk of being obese adults and developing comorbidities, such as diabetes and cardiovascular diseases.3-7

Evidence suggests that the consumption of sugar-sweetened beverages (SSBs) has increased in parallel to overweight and obesity trends.8-11 Currently, SSBs contribute between 10% and 15% of youth's caloric intake and are the primary source of added sugar in the diet of children and adolescents.12 Approximately 25% of US adolescents consume more than 750 mL of SSBs per day, which represents more than 350 calories.10,13

Numerous studies, reviews, and meta-analyses evaluating the association between SSBs and weight gain, overweight, and obesity in childhood and adolescence have been published, with some finding a positive association and others finding none. These contradictive findings have fueled intense debates, as illustrated in a pro versus con debate regarding the role of SSBs in obesity published in 2013, highlighting divergent expert opinions.8,14 Some experts argued that evidence supporting a causal relation between SSB intake and weight outcomes was sufficient,8 whereas other experts considered it to be weak.14 More recently, a systematic review showing mixed findings supplemented to the ongoing debate.15 These conflicting results may be owing to methodological issues in original studies and reviews.

Three reviews of reviews regarding SSB consumption and health outcomes among children and adults have previously been published.11,16,17 Two of these reviews11,16 studied different health outcomes, and their aims were not toward critically assessing the association between SSB consumption and obesity. Indeed, Weed and colleagues assessed the quality of reviews on SSBs and health outcomes and found that most reviews lacked comprehensive reporting of epidemiological evidence and use of systematic methodologies. The aim of the review by Althuis and Weed was to show the usefulness of evidence mapping among primary studies of SSBs and four health outcomes. Their findings showed great study-level methodological variability.11,16 The third review,17 examining SSBs and body weight, assessed how reviews' conclusions relate to their quality and source of funding. The results showed that quality scores were not correlated with reviews' conclusions or with the source of funding. However, industry-funded reviews were more likely to report weak evidence between SSB consumption and weight gain.

The primary aim of the present review of reviews was to assess how review- and study-level methodological factors explain conflicting results across reviews and meta-analyses by providing an up-to-date synthesis of recent evidence regarding the association between SSB consumption and weight gain, overweight, and obesity in a population of 6-month-old to 19-year-old children and adolescents. …